Structural polymeric foamed materials include a plurality of voids, also called cells, in a polymer matrix. A number of techniques for processing polymeric material to produce foamed parts are known in the art. Example techniques may utilize an extruder which plasticates polymeric material by the rotation of a screw within a barrel. In certain processes, a physical blowing agent may be injected into molten polymeric material, for example, through a blowing agent port formed within the barrel of the extruder, to form a mixture of polymeric material and blowing agent. The mixture may then be processed (e.g., extruded, blow molded, or injection molded) to form the desired polymeric foam article.
While such methods may be used to produce a variety of foamed parts, a need exists for improved processes associated with the injection molding of polymeric materials in the production of various foamed parts for use, for example, in the footwear industry.